Clutch actuating device for use in a vehicle drivetrain subassembly

Abstract

A clutch actuating device for use in a vehicle drivetrain subassembly having a clutch and a rotatable drive member, comprising a first rotating member which is coupled to the drive member and a second rotating member which is free to rotate relative to the drive member. The first and second rotating members are differentially driven by a gear device and may include first and second ramp surfaces which engage one another so as to permit axial translation of the members relative to one another or alternatively, may comprise threaded screw members which engage one another so as to permit axial translation relative to one another. First and second pilot clutches comprising at least one rotatable plate are provided, with at least one of the pilot clutches being connected to the gear device. Pilot clutch activating devices are provided for selectively activating, and thereby selectively grounding, the first and second pilot clutches, wherein activating one of the first and second pilot clutches causes the second rotating member to translate axially relative to the first rotating member so as to load the drivetrain subassembly clutch, and wherein activating the other of the first and second pilot clutches causes the second rotating member to translate axially relative to the first rotating member so as to unload the drivetrain subassembly clutch.

What is claimed is: 
     
       1. A clutch actuating device for use in a vehicle drivetrain subassembly having a clutch, said clutch actuating device comprising: a first rotating member which is coupled to a rotatable drive member of the vehicle drivetrain subassembly for rotation therewith;   a second rotating member which is free to rotate relative to the drive member, said first and second rotating members engaging one another so as to cause axial translation of said second member relative to said first member in response to relative rotation between said first and second members;   gear means connected to at least one of said first and second rotating members for differentially driving said first and second rotating members;   first and second pilot clutches, each of said pilot clutches comprising at least one rotatable plate, wherein said at least one rotatable plate of at least one of said first and second pilot clutches is connected to said gear means;   means for selectively activating said first pilot clutch and said second pilot clutch so as to selectively ground said first and second pilot clutches, wherein activating one of said first and second pilot clutches causes said second rotating member to translate axially relative to said first rotating member so as to load the drivetrain subassembly clutch, and wherein activating the other of said first and second pilot clutches causes said second rotating member to translate axially relative to said first rotating member so as to unload the drivetrain subassembly clutch.   
     
     
       2. The clutch actuating device as recited in claim 1, wherein said first and second rotating members have first and second ramp surfaces, respectively, said first and second ramp surfaces engaging one another so as to permit axial translation of said second rotating member relative to said first rotating member. 
     
     
       3. The clutch actuating device as recited in claim 1, wherein said first and second rotating members comprise first and second rotating sleeve members, respectively, wherein said first and second rotating sleeve members are threaded screw members which engage one another in a linear screw arrangement so as to permit axial translation of said second rotating sleeve member relative to said first rotating sleeve member. 
     
     
       4. The clutch actuating device as recited in claim 2, wherein said first and second ramp surfaces comprise single directional ramp surfaces. 
     
     
       5. The clutch actuating device as recited in claim 1, wherein said gear means comprises a planetary gear set which includes a planet carrier coupled to the rotatable drive member of the vehicle drivetrain subassembly for rotation therewith, a plurality of planet gears mounted on the planet carrier, a ring gear and a sun gear. 
     
     
       6. The clutch actuating device as recited in claim 5, wherein: said first and second rotating members comprise first and second rotating sleeve members, respectively;   said planet carrier is attached to said first rotating sleeve member for rotation therewith;   said ring gear is integral with said second rotating sleeve member for rotation therewith;   said sun gear is rotatably mounted to the rotatable drive member.   
     
     
       7. The clutch actuating device as recited in claim 6, wherein: said at least one plate of said first pilot clutch is splined to said ring gear;   said at least one plate of said second pilot clutch is splined to said sun gear;   activating said first pilot clutch so as to ground said at least one plate of said first pilot clutch produces relative rotation between said first and second rotating sleeve members causing said second rotating sleeve member to translate axially relative to said first rotating sleeve member so as to load the drivetrain subassembly clutch for a first direction of rotation of the drive member of the drivetrain subassembly, and wherein activating said first pilot clutch causes said second rotating sleeve member to translate axially relative to said first rotating sleeve member so as to unload the drivetrain subassembly clutch for a second direction of rotation of the drive member, the second direction of rotation being opposite to the first direction of rotation;   activating said second pilot clutch so as to ground said at least one plate of said second pilot clutch produces relative rotation between said first and second rotating sleeve members which causes said second rotating sleeve member to translate axially relative to said first rotating sleeve member so as to unload the drivetrain subassembly clutch for the first direction of rotation of the drive member, and wherein activating said second pilot clutch causes said second rotating sleeve member to translate axially relative to said first rotating sleeve member so as to load the drivetrain subassembly clutch for the second direction of rotation of the drive member.   
     
     
       8. The clutch actuating device as recited in claim 5, wherein: said planet carrier is fixedly attached to said first rotating member for rotation therewith;   said ring gear is drivingly connected to said second rotating member;   said sun gear is rotatably mounted to said second rotating member;   said first rotating member includes an inner threaded screw member which engages threads formed on said second rotating member so as to form a linear screw arrangement.   
     
     
       9. The clutch actuating device as recited in claim 8, wherein: said at least one plate of said first pilot clutch is splined to said sun gear;   said at least one plate of said second pilot clutch is splined to said second rotating member;   wherein activating said first pilot clutch causes said second rotating member to translate axially relative to said first rotating member so as to load the drivetrain subassembly clutch for a first direction of rotation of the drive member, and wherein activating said first pilot clutch causes said second rotating member to translate axially relative to said first rotating member so as to unload the drivetrain subassembly clutch for a second direction of rotation of the drive member, the second direction of rotation being opposite to the first direction of rotation:   wherein activating said second pilot clutch causes said second rotating member to translate axially relative to said first rotating member so as to unload the drivetrain subassembly clutch for the first direction of rotation of the drive member, and wherein activating said second pilot clutch causes said second rotating member to translate axially relative to said first rotating member so as to load the drivetrain subassembly clutch for the second direction of rotation of the drive member.   
     
     
       10. The clutch actuating device as recited in claim 1, wherein said activating means comprises: a reaction plate fixed to a housing of the drivetrain subassembly and disposed axially between said first pilot clutch and said second pilot clutch;   first and second armature plates disposed axially adjacent said first and second pilot clutches, respectively, so that said first pilot clutch is disposed axially between said first armature plate and said reaction plate and said second pilot clutch is disposed axially between said second armature plate and said reaction plate;   first and second electromagnets disposed axially adjacent said first and second armature plates, respectively;   wherein energizing a coil of said first electromagnet causes said at least one rotatable plate of said second clutch to be urged against said reaction plate thereby grounding said second pilot clutch and wherein energizing a coil of said second electromagnet causes said at least one rotatable plate of said first pilot clutch to be urged against said reaction plate thereby grounding said first pilot clutch.   
     
     
       11. The clutch actuating device as recited in claim 1, wherein said gear means comprises a bevel gear set which includes a pinion gear and first and second bevel side gears. 
     
     
       12. The clutch actuating device as recited in claim 11, wherein said pinion gear is pinned to the rotatable drive member of the vehicle drivetrain subassembly for rotation therewith and said first and second bevel side gears engage the rotatable drive member in a slip fit so that said first and second bevel side gears are free to rotate relative to the drive member. 
     
     
       13. The clutch actuating device as recited in claim 12, wherein: said at least one rotatable plate of said first pilot clutch is connected to said first bevel side gear;   said at least one rotatable plate of said second pilot clutch is connected to said second bevel side gear and said second rotating member; and   said first rotating member comprises a clutch hub of the vehicle drivetrain subassembly clutch and said second rotating member is a rotating sleeve member.   
     
     
       14. The clutch actuating device as recited in claim 1, wherein said means for selectively activating said first and second pilot clutches comprises an electromagnet having first and second coils which are concentric with one another. 
     
     
       15. The clutch actuating device as recited in claim 1, wherein said first pilot clutch comprises a plurality of rotatable plates connected to said gear means and said second pilot clutch comprises a plurality of rotatable plates connected to said gear means. 
     
     
       16. The clutch actuating device as recited in claim 15, wherein each of said rotatable plates of said first and second pilot clutches include a plurality of circumferentially spaced and circumferentially extending slots. 
     
     
       17. The clutch actuating device as recited in claim 1, wherein said first rotating member comprises a pressure plate which is splined to the rotatable drive member of the vehicle drivetrain subassembly and is disposed axially adjacent to the clutch of the drivetrain subassembly. 
     
     
       18. The clutch actuating device as recited in claim 17, wherein: said pressure plate includes a first axially facing ramp surface which engages a second axially facing ramp surface attached to said second rotating member, said first and second ramp surfaces engage one another so as to cause said pressure plate to translate axially relative to said second rotating member in response to relative rotation between said pressure plate and said second rotating member.   
     
     
       19. The clutch actuating device as recited in claim 18, wherein: said gear means comprises a bevel gear set which is coupled to a planetary gear set; and   said planetary gear set is drivingly connected to said second rotating member.   
     
     
       20. The clutch actuating device as recited in claim 19, wherein a first one of said first and second pilot clutches is connected to a planet carrier of said planetary gear set and the other of said first and second pilot clutches is connected to a bevel side gear of said bevel gear set. 
     
     
       21. The clutch actuating device as recited in claim 13, wherein: said rotating sleeve member is coupled to a pressure plate connecting member via a thrust bearing;   said pressure plate connecting member includes a plurality of circumferentially spaced and axially extending arms which pass through corresponding ones of a plurality of circumferentially spaced slots in said clutch hub; and   said clutch actuating device further comprises a pressure plate which is secured to said arms of said pressure plate connecting member.